Trains traveling on railroads often move into and out of different jurisdictions or railways owned and operated by different entities on a regular basis. The ability to fully monitor the status of trains on different railways and in rail yards operated by different entities is limited. Often times, these trains also enter rail yards to undergo various services, either as part of normal train operations, as part of maintenance or inspections. When a train enters a rail yard, one or more railcars may be removed from the train and other railcars added, depending on the train route and the ultimate destination of the railcars. Therefore, the particular composition of a train will change as it enters and leaves each rail yard. Because individual railcars in a train may have different points of departure and different destinations, it is critical that each railcar in a train be identified and tracked. In addition, information related to individual railcars in a train needs to be communicated to the owner or operator of the train itself. Finally, it is essential to be able to identify a group of train cars which are coupled together as this changes as trains enter and subsequently depart a rail yard. A group of train cars which are coupled together and operate as a unit are referred to in the art as a Consist.
In the prior art, information relating to which cars form part of a Consist has been communicated manually to various entities, either by scanning an identifier on each railcar or by manual data entry, for example. However, each of these procedures have their flaws as they are heavily dependent on a human operator. There has heretofore been no way known to the applicant for an original operator or owner of a train to ensure knowledge of which train cars form a Consist once the train has been modified at a yard operated by another operator. Rather, once the train has returned to a yard or inspection station operated by the original operator, then the cars which form the Consist are logged. Alternatively, this information must be requested from the yard having performed the modifications to the Consist, and this information may not always be reliable or timely.
More recently, railcars have been equipped with radio frequency identification (RFID) tags. RFID tags can be either passive or active in nature. Passive tags need to pass within close proximity of a receiver before sending a signal identifying the car. Such receivers are often placed at the entrance or exit to a train yard. Active tags are used in trains equipped with real time locating systems (RTLS), within a predefined geographic area such that the trains can be located or identified at positions other than at the entrance or exit of the yard. While the provision of an RTLS system aboard a train serves to identify where a train is, there is no way to know whether cars in close proximity are actually coupled together, or which cars in a particular geographic area form a Consist. RTLS technology is not accurate enough to pinpoint the exact location of a train car, and even if it were, this would not be sufficient to confirm whether two cars close to each other were coupled together in a Consist. Accordingly, there is a need in the art for a method and system capable of accurately identifying where two or more cars are so coupled together to form a Consist.